1. Field of the Invention
This invention relates to improvements in meter risers and more particularly, but not by way of limitation, to an improved means for connecting plastic pipe to metallic connection members and protecting the plastic pipe against adverse environmental conditions.
2. Description of the Prior Art
In the gas distribution industry, and the like, wherein natural gas, or other fluids, are transmitted to a plurality of individual consumers by a main distribution system, which is normally buried, and which transports or directs the fluid to individual distribution lines having meters interposed therein which are normally disposed above the ground. In the past, the pipe lines of the main distribution system as well as the individual lines and all of the connecting members were metallic, but in recent years the use of plastic materials has become widespread and it is common practice to use plastic pipe for transmitting or transporting the gas or other fluids. A problem exists, however, in that many plastic materials melt or flow at relatively low temperatures, and any exposure of the plastic material to direct sunlight, or relatively high ambient temperatures may deform or otherwise damage the plastic pipe, which may cause undesirable leakage of the gas or fuel therefrom. As a consequence, safety codes in many places prohibit the use of plastic pipe above the surface of the ground for connection with the meter.
In order to overcome this problem, the gas distribution industry, and the like, has provided relatively short lengths of metal pipe, called meter risers, which attach to the buried plastic pipe, and bend upwardly and extend above the surface of the ground for connection with the meter. One disadvantage of this solution to the problem is that the metallic pipe is surrounded by the earth between the connection thereof with the plastic pipe and the surface of the ground, and galvanic action erodes the metallic pipe, causing leakage. As a result it is necessary to connect anodes to the metallic pipe, or otherwise protect the metallic pipe from the corrosion due to the galvanic action. In addition, it is necessary to periodically inspect the buried metallic pipe for ascertaining that the anodes are functioning properly, or that the pipe is being properly protected against erosion. It will be apparent that this increases the expense of using metallic pipe, and greatly adds to the inconvenience in the use thereof, rendering the use of metallic meter risers undesirable.